The present invention relates to a functional orthodontic appliance with an exraoral aid for treating malpositions of the jaw or teeth. Distal occlusion is a malposition of the jaw or teeth which often occurs. One cause is maxillary prognathisim which manifests itself in the protrusion of the upper jaw beyond its normal extent. The upper jaw is too large or is dislocated to the front in contrast to the normal occlusion or eugrathic occlusion. A second cause is a mandibular retrognathisim. This manifests itself by a retruded lower jaw. A third cause is maxillary dentoalveolar protrusion. It manifests itself in a protrusion of the teeth of the upper jaw when the jaw relation is correct. The treatment today is effected in a standard manner by way of orthodontic apparatus which are stationarily positioned or may be removed, or by way of functional orthodontic appliances (FO-appliances). An additional surgical orthodontic treatment is only required in particularly cases which are resistant to therapy.
The most varied of dentition regulators are known on the market under the collective term of FO-appliances, which although being based on similar active principles, however greatly vary in their manner of design and their constructional shape. Common to all FO-appliances is the fact that they act simultaneously on the upper and lower jaw and the correction of the malposition is achieved by way of a targeted diversion (deflection) of the muscular forces acting in the region of the mouth. The basis or therapy by way of FO-appliances lies in training away the restricting malfunctions of the muscle system, and thus a correction of the functional malposition of the lower jaw is achieved. Painful or damaging overloading of the tissue is avoided since the person being treated to a certain extent may meter the correcting force himself.
Known FO-for example include the activator according to Adresen and H{hacek over (a)}upl, the bionator according to Balters, the dentition shaper according to Bimler, the elastically-open activator according to Klammt, the kinetor according to Stockfisch, the cybernator, the denudated activator, the functionator (FIO), the twin-bloc appliance, the Zürcher activator to Teuscher, and the regulator according to Fr{hacek over (a)}nkel.
The apparatus which are often grouped under the term “activators” are more or less rigid appliances, which lie loosely in the mouth and have no fixed holding elements on the teeth. They must be held in a certain position by the muscle system and act as activators for the chewing and lip muscle system. Above all, the control of the growth of the jaw and the correction of the malposition of the upper and lower jaw to one another is to be achieved by way of this. For this, the muscular forces are diverted or directed in a desired direction so that the growth of the jaw is likewise effected in the desired position, finally resulting in the compensation of the malposition.
Since the success of the therapy depends on the growth, the FO-appliances are preferably applied with young and very young patients, to some extent still having milk teeth, but mainly having a mixed dentition, which entails very special problems with regard to their acceptance and discipline with regard to their wearing.
The function regulator according to Fränkel effects the correction of the jaw exclusively via the muscle system. Therapy with the Fränkel functional regulator necessitates a habitual phase in which the dysfunctional muscle system is trained and strengthened during the day by way of the Fränkel FO-appliance. This training is increased until in the actual treatment phase the appliance may be worn during the day and above all, also at night. The regression of the lower jaw is observed as a result of a functional and postural weakness of the muscle system. This is stimulated by way of a plate which on the inside below the front of the lower jaw bears on the lip, and is actively brought into the desired position by the wearer so that a sinking of the lower jaw is avoided. The plates do not serve as mechanical bearings, but they represent a mechanical stimulus which does not directly load the tissue. With the functional regulators according to Fränkel, apart from lip plates or pads, cheek plates having a large area are held distanced by a few millimeters from the jaw by way of a complex wire skeleton. Three to four of the Fränkel appliances are required for the complete treatment since adaptations of the individual apparatus to the growth of the jaw are not possible. With deciduous dentition, with the Fränkel appliance the problem of toothing inhibition occurs which may even lead to a stoppage of the therapy. The Fränkel function regulator may neither be combined with brackets nor with headgear.
If malpositions are present which may not be adequately treated with removable or fixed braces alone, then additional forces are introduced with extraoral appliances, preferably external braces or headgear. The main functions of the external brace lies in a) rearwardly correcting the position of lateral teeth in the upper jaw which project too much to the front, b) preventing correctly seated lateral teeth from sliding forward and c) retarding the upper jaw in growth with respect to the lower jaw. The external brace consists of a facebow and a head or neck strip. The facebow in turn is constructed of an inner and outer bow which in each case is formed of strong metal wires and are connected centrally in the transition region. The inner bow at its end region is detachably fastened on removable plates or stationary appliances. It is preferably inserted into small tubes which with strips are fastened to the molar teeth. The often thicker outer bow transmits the tensile forces from the strip system bearing on the head and/or neck (neck strip and/or head cap) onto the inner bow and thus onto the teeth in the lower jaw.
With regard to the head-car or Teuscher activator, the combination of a bimaxillary monoblock appliance with an outer bow is known as an extraoral aid for treating an extreme distocclusion. If such appliance, are used for a less acute prognathism, then at the location of the desired moderate correction however an overcompensation and an artificially induced protrusion of the lower jaw or other malpositions may occur.
The treatment with FO-appliances often lasts longer that of fixed appliances and for example only permits the targeted positional change of individual teeth to a limited extent. Known FO-appliances often entail great handicaps on speaking and their success is heavily dependent on the cooperation of the very often young patients. Furthermore they may not be used simultaneously with stationary (fixed) appliances.